A chick, the result of the successful hatching of 26 chickens from synthetic eggs announced by Colossal Biosciences.
After the giant wolf, the mammoth rat and the dodo, Colossal brought back the theme of de-extinction with “a big step towards bringing back the dodo and the giant moa”. But is it really so?
Colossal Biosciences has done its thing again. This time, the Texas-based company the birth of 26 healthy chickens through what he calls “Colossal artificial egg”describing it as a big step “towards the de-extinction of the dodo and the giant moa”.
According to the announcement, made on the 19th, the idea is not just to imitate a natural egg, but to reformulate part of its structure so that it can serve specific research and, eventually, conservation objectives.
But Colossal, already known for its highly ambitious biotechnology projects, once again created controversy in the scientific community, with yet another announcement not accompanied by public data or a peer-reviewed scientific article, according to .
What Colossal did differently
The magazine begins by explaining that for decades scientists have been trying to reproduce the sophisticated egg in the laboratory, namely the shell that protects the embryo and allows gas exchange, conserves moisture and creates a biologically stable environment for all stages of development. To date, they have all failed.
The innovation presented by Colossal is based on a semi-permeable membrane silicone-based, placed inside a rigid, hexagonal structure. According to the company, this membrane allows oxygen to pass through in a similar way to the shell of a real egg, while keeping moisture inside.
Supposedly, the device also includes a transparent window which allows researchers to directly observe the development of the embryo.
The chicken (real) came before the egg (artificial)
If the technology works as the company says, it is a historic advance for developmental biology, confesses National Geographic. But several experts emphasize that this solution represents only part of the challenge. Especially because Colossal’s artificial egg does not replace — at least, for now — the entire reproductive process of a bird.
According to Colossal’s description, scientists select eggs laid by chickens in the last 24 to 48 hours, open them and transfer the contents to the artificial system. That is, fertilization, the initial formation of the embryo, the yolk and other essential structures continue to depend on a real chicken.
De-extinction is more difficult in birds
This detail is particularly important when talking about de-extinctionthe theme that put Colossal on the map in recent years, with an attempt to , with the creation of a trying to bring back the woolly mammoth or, don’t forget, with the “colossal” announcement that the famous — a novelty , later, by the company itself.
Resurrecting an extinct bird wouldn’t just require incubating an embryo in an artificial container. It would be necessary to genetically alter cells at a very early stage in order to produce an animal with characteristics close to the disappeared species. In birds, this is much more difficult than in mammals, experts warn.
While mammalian embryos can be manipulated at an early stage and then implanted into a replacement uterus, in birds, the development of the embryo, yolk and shell occurs within the mother’s body.
One of the most promising approaches involves calls primordial germ cellsprecursors of sperm and eggs. In theory, these cells can be isolated, cultured, genetically edited and introduced into live birds, which could then in theory produce offspring with desired changes. Colossal says it has already taken steps in this direction, namely with germ cells from common pigeons, a species related to the Nicobar pigeon, which the company sees as a possible model for projects linked to the dodo.
In the case of the giant moa, a bird from New Zealand that could reach almost 3.7 meters in height, the problem would be even greater: the embryo could exceed the capacity of any egg from a living species used as a substitute. This is where the artificial egg could, in theory, play a role, allowing the embryo to be transferred to a larger system during development.
Even so, experts interviewed by National Geographic emphasize that there are many obstacles ahead. Colossal has not yet released key data, such as the hatch rate achieved with the new system, nor has it provided results that can be independently evaluated.
Tomás Guimarães, ZAP //
